I don't understand your request.
What do you mean by: "In my master record this field is set to N/A by a creation script."? What is your "master record" and in which table does it exist?
Are you trying to keep users from modifying certain records in the table from which the value list lists values or in the table where your pop up menu enters data?
Yes I didn't explain that well did I?
My system is for an electrical application. For the purposes of this conversation there are three primary tables.
>>Tests >> Boards >> Circuits
When a test is created a primary board, identified as "Source" is created. Boards have circuits, circuits feed boards, boards feeds circuits etc etc. This can cascade 100 deep. There are three instances of circuits. Parent Circuit feeds a board, a board has Child Circuits. The there is also a Source circuit
The user can, within a board, select which board feeds it and then which related child circuit feeds it. This works really well via a popup menu system.
I need to prohibit modification, via the 2 popups, of the Source feed circuit for the primary source board. Both have a field which identifies them as Source if that helps
So if a field identifies the board or circuit as "Source" what then cannot be modified? All other fields in that record? Child records cannot then be linked to a different Source record or ???